Practice Guidelines

The 2001 Recommended Childhood Immunization Schedule

RICHARD KENT ZIMMERMAN, M.D., M.P.H., University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania

Am Fam Physician. 2001 Jan 1;63(1):151-155.

The collaboration of the Advisory Committee on Immunization Practices (ACIP), the American Academy of Pediatrics (AAP) and the American Academy of Family Physicians (AAFP) continues with the 2001 Recommended Childhood Immunization Schedule (see page 152). Several important changes occurred this year and AAFP had active input into the schedule.

Whereas the schedule previously showed a preference for administering hepatitis B vaccine at birth, there is no longer such a preference because combination vaccines that include hepatitis B are now available. One such combination vaccine is currently licensed and another may be licensed in the near future. Nonetheless, children born to mothers who are positive for hepatitis B surface antigen should receive hepatitis B immune globulin and the first dose of hepatitis B vaccine within the first 12 hours of birth. Hepatitis B vaccine for children is now free of thimerosal as are Haemophilus influenzae type b (Hib) conjugate vaccines.

For 2001, the all-inactivated poliovirus vaccine (IPV) is recommended to eliminate the risk of vaccine-associated paralytic poliomyelitis (VAPP) that can occur with administration of oral poliovirus vaccine (OPV). Because of the risk of VAPP, the majority of parents prefer a vaccine schedule that starts with IPV even though extra injections are required.

The biggest change in the routine schedule is the addition of pneumococcal conjugate vaccine (PCV). Streptococcus pneumoniae causes approximately 3,000 cases of meningitis, 61,000 cases of bacteremia, 100,000 to 135,000 cases of pneumonia requiring hospitalization and 7 million cases of otitis media annually in the United States.1 Risk factors for invasive pneumococcal disease include age, race, recent use of antibiotics, day care attendance, passive smoking and chronic medical conditions such as sickle cell disease and human immunodeficiency virus (HIV) infection. Heightening the importance of immunization is the increasing proportion of S. pneumoniae that is resistant to antibiotics.

A heptavalent PCV was licensed in the year 2000 in the United States. The vaccine is immunogenic.2,3 The carrier protein is CRM197, which has been used in one Hib vaccine. PCV does not contain thimerosal. The vaccine was designed to cover the seven serotypes (4, 6B, 9V, 14, 18C, 19F and 23F) most common in children; in fact, these serotypes account for about 80 percent of invasive infections in children younger than six years but only 50 percent of infections in those six years and older.

A randomized, double-blind, controlled trial4 was conducted at Northern Kaiser Permanente (Calif.). In the primary analysis, the efficacy of PCV was 100 percent. Eight months later in the follow-up analysis, the vaccine efficacy against invasive disease was 94 percent for serotypes included in the vaccine in the intent-to-treat analysis and 97 percent for serotypes in the vaccine among patients who were fully vaccinated. No serious adverse reactions were associated with PCV. When PCV was given with diphtheria and tetanus toxoids and acellular pertussis but at another injection site, fever of 38°C (100.4°F) occurred in 15 to 24 percent of those vaccinated with PCV compared with 9 to 17 percent of those receiving the control vaccine (experimental meningococcal conjugate vaccine).4 Among persons receiving PCV, 10 to 14 percent developed redness at the injection site and 15 to 23 percent developed tenderness at the injection site.4 The break even price is $46 per dose from the societal perspective and $18 per dose from the health care payer's perspective.5 The manufacturer's list price is $58 per dose, making it the most expensive routine infant immunization series to date.

The AAFP, ACIP and AAP recommend PCV for routine infant immunization and catch-up vaccination of children younger than 24 months and catch-up vaccination of children 24 to 59 months of age at high risk for invasive disease, including sickle cell disease, HIV infection, chronic illness (e.g., bronchopulmonary dysplasia) and immunocompromising conditions. For infants, the routine vaccine schedule is two, four, six and 12 to 15 months. A special schedule is needed for catch-up vaccinations because the number of doses varies by age and by presence of high-risk medical conditions; see the manufacturer's package insert or ACIP recommendations. The information on the minimal age for initial childhood vaccinations and minimal interval between vaccine doses, by type of vaccine, is given in the accompanying table on page 154.6

Recommended Childhood Immunization Schedule, United States—January 2001 to December 2001

note: Vaccines are listed under routinely recommended ages. Clear bars indicate range of recommended ages for immunization. Any dose not given at the recommended age should be given as a “catch-up” immunization at any subsequent visit when indicated and feasible. Shaded ovals indicate vaccines to be given if previously recommended doses were missed or given earlier than the recommended minimum age. Information in bold type has been added by the American Academy of Family Physicians (AAFP).

*—This schedule has been approved by the Advisory Committee on Immunization Practices (ACIP), the American Academy of Pediatrics (AAP) and the AAFP. It indicates the recommended ages for routine administration of currently licensed childhood vaccines, as of November 1, 2000, for children through 18 years of age. Additional vaccines may be licensed and recommended during the year. Licensed combination vaccines may be used whenever any components of the combination are indicated and its other components are not contraindicated. Providers should consult the manufacturers' package inserts for detailed recommendations.

†—Infants born to hepatitis B surface antigen (HBsAg)-negative mothers should receive the first dose of hepatitis B (Hep B) vaccine by age two months. The second dose should be given at least one month after the first dose. The third dose should be administered at least four months after the first dose and at least two months after the second dose, but not before six months of age for infants. Infants born to HBsAg-positive mothers should receive hepatitis B vaccine and 0.5 mL hepatitis B immune globulin (HBIG) within 12 hours of birth at separate sites. The second dose is recommended at one to two months of age and the third dose at six months of age. Infants born to mothers whose HBsAg status is unknown should receive hepatitis B vaccine within 12 hours of birth. Maternal blood should be drawn at the time of delivery to determine the mother's HBsAg status; if the HBsAg test is positive, the infant should receive HBIG as soon as possible (no later than one week of age). All children and adolescents who have not been immunized against hepatitis B should begin the series during any visit. Special efforts should be made to immunize children who were born in or whose parents were born in areas of the world with moderate or high endemicity of hepatitis B virus infection.

‡—The fourth dose of diphtheria and tetanus toxoids and acellular pertussis vaccine (DTaP) may be administered as early as 12 months of age, provided six months have elapsed since the third dose and if the child is unlikely to return at age 15 to 18 months. Tetanus and diphtheria toxoids (Td) immunization is recommended at 11 to 12 years of age if at least five years have elapsed since the last dose of DTP, DTaP or DT. Subsequent routine Td boosters are recommended every 10 years.

§—Three Haemophilus influenzae type b (Hib) conjugate vaccines are licensed for infant use. If PRP-OMP (PedvaxHIB and Comvax) is administered at two and four months of age, a dose at six months is not required. Because clinical studies in infants have demonstrated that using some combination products may induce a lower immune response to the Hib vaccine component, DTaP/Hib combination products should not be used for primary immunization in infants at two, four or six months of age, unless it is approved by the U.S. Food and Drug Administration for these ages.

‖—An all-inactivated poliovirus vaccine (IPV) schedule is recommended for routine childhood polio vaccination in the United States. All children should receive four doses of IPV at two months, four months, six to 18 months, and four to six years of age. Oral poliovirus vaccine (OPV) should be used only in selected circumstances. (See MMWR Morb Mortal Wkly Rep May 19, 2000;49[RR-5]:1–22.)

¶—The heptavalent conjugate pneumococcal vaccine (PCV) is recommended for all children two to 23 months of age. It also is recommended for certain children 24 to 59 months of age. (See MMWR Morb Mortal Wkly Rep October 6, 2000;49[RR-9]:1–35.) The full AAFP Clinical Policy on Pneumococcal Conjugate Vaccine is available athttp://www.aafp.org/policy/camp/24.html.

#—The second dose of measles, mumps, rubella (MMR) vaccine is recommended routinely at four to six years of age, but may be administered during any visit, provided that at least four weeks have elapsed since receipt of the first dose and that both doses are administered beginning at or after 12 months of age. Those who have not previously received the second dose should complete the schedule by the 11- to 12-year-old visit.

**—Varicella (Var) vaccine is recommended at any visit on or after the first birthday for susceptible children, i.e., those who lack a reliable history of chickenpox (as judged by a health care provider) and who have not been immunized. Susceptible persons 13 years or older should receive two doses, given at least four weeks apart.

††—Hepatitis A (Hep A) is shaded to indicate its recommended use in selected states and/or regions, and for certain high-risk groups; consult your local public health authority. (Also, see MMWR Morb Mortal Wkly Rep October 1, 1999;48[RR-12]:1–37.)

For additional information about the vaccines listed above, please visit the National Immunization Program Home Page athttp://www.cdc.gov/nip/ or call the National Immunization Hotline at 800-232-2522 (English) or 800-232-0233 (Spanish).

This schedule is provided by the American Academy of Family Physicians only as an assistance for physicians making clinical decisions regarding the care of their patients. As such, they cannot substitute for the individual judgment brought to each clinical situation by the patient's family physician. As with all clinical reference resources, they reflect the best understanding of the science of medicine at the time of publication, but they should be used with the clear understanding that continued research may result in new knowledge and recommendations.

Recommended Childhood Immunization Schedule, United States—January 2001 to December 2001

note: Vaccines are listed under routinely recommended ages. Clear bars indicate range of recommended ages for immunization. Any dose not given at the recommended age should be given as a “catch-up” immunization at any subsequent visit when indicated and feasible. Shaded ovals indicate vaccines to be given if previously recommended doses were missed or given earlier than the recommended minimum age. Information in bold type has been added by the American Academy of Family Physicians (AAFP).

*—This schedule has been approved by the Advisory Committee on Immunization Practices (ACIP), the American Academy of Pediatrics (AAP) and the AAFP. It indicates the recommended ages for routine administration of currently licensed childhood vaccines, as of November 1, 2000, for children through 18 years of age. Additional vaccines may be licensed and recommended during the year. Licensed combination vaccines may be used whenever any components of the combination are indicated and its other components are not contraindicated. Providers should consult the manufacturers' package inserts for detailed recommendations.

†—Infants born to hepatitis B surface antigen (HBsAg)-negative mothers should receive the first dose of hepatitis B (Hep B) vaccine by age two months. The second dose should be given at least one month after the first dose. The third dose should be administered at least four months after the first dose and at least two months after the second dose, but not before six months of age for infants. Infants born to HBsAg-positive mothers should receive hepatitis B vaccine and 0.5 mL hepatitis B immune globulin (HBIG) within 12 hours of birth at separate sites. The second dose is recommended at one to two months of age and the third dose at six months of age. Infants born to mothers whose HBsAg status is unknown should receive hepatitis B vaccine within 12 hours of birth. Maternal blood should be drawn at the time of delivery to determine the mother's HBsAg status; if the HBsAg test is positive, the infant should receive HBIG as soon as possible (no later than one week of age). All children and adolescents who have not been immunized against hepatitis B should begin the series during any visit. Special efforts should be made to immunize children who were born in or whose parents were born in areas of the world with moderate or high endemicity of hepatitis B virus infection.

‡—The fourth dose of diphtheria and tetanus toxoids and acellular pertussis vaccine (DTaP) may be administered as early as 12 months of age, provided six months have elapsed since the third dose and if the child is unlikely to return at age 15 to 18 months. Tetanus and diphtheria toxoids (Td) immunization is recommended at 11 to 12 years of age if at least five years have elapsed since the last dose of DTP, DTaP or DT. Subsequent routine Td boosters are recommended every 10 years.

§—Three Haemophilus influenzae type b (Hib) conjugate vaccines are licensed for infant use. If PRP-OMP (PedvaxHIB and Comvax) is administered at two and four months of age, a dose at six months is not required. Because clinical studies in infants have demonstrated that using some combination products may induce a lower immune response to the Hib vaccine component, DTaP/Hib combination products should not be used for primary immunization in infants at two, four or six months of age, unless it is approved by the U.S. Food and Drug Administration for these ages.

‖—An all-inactivated poliovirus vaccine (IPV) schedule is recommended for routine childhood polio vaccination in the United States. All children should receive four doses of IPV at two months, four months, six to 18 months, and four to six years of age. Oral poliovirus vaccine (OPV) should be used only in selected circumstances. (See MMWR Morb Mortal Wkly Rep May 19, 2000;49[RR-5]:1–22.)

¶—The heptavalent conjugate pneumococcal vaccine (PCV) is recommended for all children two to 23 months of age. It also is recommended for certain children 24 to 59 months of age. (See MMWR Morb Mortal Wkly Rep October 6, 2000;49[RR-9]:1–35.) The full AAFP Clinical Policy on Pneumococcal Conjugate Vaccine is available athttp://www.aafp.org/policy/camp/24.html.

#—The second dose of measles, mumps, rubella (MMR) vaccine is recommended routinely at four to six years of age, but may be administered during any visit, provided that at least four weeks have elapsed since receipt of the first dose and that both doses are administered beginning at or after 12 months of age. Those who have not previously received the second dose should complete the schedule by the 11- to 12-year-old visit.

**—Varicella (Var) vaccine is recommended at any visit on or after the first birthday for susceptible children, i.e., those who lack a reliable history of chickenpox (as judged by a health care provider) and who have not been immunized. Susceptible persons 13 years or older should receive two doses, given at least four weeks apart.

††—Hepatitis A (Hep A) is shaded to indicate its recommended use in selected states and/or regions, and for certain high-risk groups; consult your local public health authority. (Also, see MMWR Morb Mortal Wkly Rep October 1, 1999;48[RR-12]:1–37.)

For additional information about the vaccines listed above, please visit the National Immunization Program Home Page athttp://www.cdc.gov/nip/ or call the National Immunization Hotline at 800-232-2522 (English) or 800-232-0233 (Spanish).

This schedule is provided by the American Academy of Family Physicians only as an assistance for physicians making clinical decisions regarding the care of their patients. As such, they cannot substitute for the individual judgment brought to each clinical situation by the patient's family physician. As with all clinical reference resources, they reflect the best understanding of the science of medicine at the time of publication, but they should be used with the clear understanding that continued research may result in new knowledge and recommendations.

Recent data indicate that allergy to gelatin is responsible for rare anaphylactic reactions to measles-mumps-rubella vaccine. Therefore, persons with anaphylaxis to gelatin should not receive vaccines containing gelatin. Clinicians should have epinephrine available for treating reactions following vaccination.

Federal law requires physicians to provide the federal Vaccine Information Statements to the patient or his or her parent or guardian for almost all childhood vaccines. The Vaccine Information Statements change periodically. An up-to-date set can be downloaded each January from the Web site of the Centers for Disease Control and Prevention (http://www.cdc.gov) or obtained from local health departments.

Progress in the development of new vaccines continues at an amazing rate. Physicians should be diligent to keep current; the following Web sites may be helpful:http://www.aafp.org;http://www.cdc.org/nip; andhttp://www.immunize.org.

*—The minimal acceptable ages and intervals may not correspond with the optimal recommended ages and intervals for vaccination. For current recommended routine schedules, see the annual Recommended Childhood Immunization Schedule on page 152.

†—This final dose of hepatitis B vaccine is recommended at least four months after the first dose and no earlier than six months of age.

‡—The total number of doses of diphtheria and tetanus toxoids should not exceed six each before the seventh birthday.

§—The booster doses of Hib and pneumococcal vaccines that are recommended following the primary vaccination series should be administered no earlier than 12 months of age and at least two months after the previous dose.

‖—For unvaccinated adults at increased risk of exposure to poliovirus with less than three months but more than two months available before protection is needed, three doses of IPV should be administered at least one month apart.

¶—If the third dose is given after the third birthday, the fourth (booster) dose is not needed.

**—Although the age for measles vaccination may be as young as six months in outbreak areas where cases are occurring in children younger than one year, children initially vaccinated before the first birthday should be revaccinated at 12 to 15 months of age and an additional dose of vaccine should be administered at the time of school entry or according to local policy. Doses of MMR or other measles-containing vaccines should be separated by at least one month.

Adapted from Epidemiology and prevention of vaccine-preventable diseases. 6th ed. Atlanta: Centers for Disease Control and Prevention, 2000.

Minimal Age for Initial Childhood Vaccinations and Minimal Interval Between Vaccine Doses by Type of Vaccine*

*—The minimal acceptable ages and intervals may not correspond with the optimal recommended ages and intervals for vaccination. For current recommended routine schedules, see the annual Recommended Childhood Immunization Schedule on page 152.

†—This final dose of hepatitis B vaccine is recommended at least four months after the first dose and no earlier than six months of age.

‡—The total number of doses of diphtheria and tetanus toxoids should not exceed six each before the seventh birthday.

§—The booster doses of Hib and pneumococcal vaccines that are recommended following the primary vaccination series should be administered no earlier than 12 months of age and at least two months after the previous dose.

‖—For unvaccinated adults at increased risk of exposure to poliovirus with less than three months but more than two months available before protection is needed, three doses of IPV should be administered at least one month apart.

¶—If the third dose is given after the third birthday, the fourth (booster) dose is not needed.

**—Although the age for measles vaccination may be as young as six months in outbreak areas where cases are occurring in children younger than one year, children initially vaccinated before the first birthday should be revaccinated at 12 to 15 months of age and an additional dose of vaccine should be administered at the time of school entry or according to local policy. Doses of MMR or other measles-containing vaccines should be separated by at least one month.

Adapted from Epidemiology and prevention of vaccine-preventable diseases. 6th ed. Atlanta: Centers for Disease Control and Prevention, 2000.

The Author

Richard K. Zimmerman, M.D., M.P.H., is an associate professor in the Department of Family Medicine and Clinical Epidemiology at the University of Pittsburgh (Pa.) School of Medicine, with a secondary appointment in the Department of Health Services Administration. He is the AAFP liaison to the Advisory Committee on Immunization Practices.